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    <a href="../index.html">cppreference.com</a> &gt; <a href=
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    fprintf
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    Syntax:
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  <pre class="syntax-box">
  #include &lt;stdio.h&gt;
  int fprintf( FILE *stream, const char *format, ... );
</pre>

  <p>The fprintf() function sends information (the arguments) according
  to the specified <em>format</em> to the file indicated by
  <em>stream</em>. fprintf() works just like <a href=
  "printf.html">printf</a>() as far as the format goes. The return
  value of fprintf() is the number of characters outputted, or a
  negative number if an error occurs. An example:</p>
  <pre class="example-code">
   char name[20] = &quot;Mary&quot;;
   FILE *out;
   out = fopen( &quot;output.txt&quot;, &quot;w&quot; );
   if( out != <strong>NULL</strong> )
     fprintf( out, &quot;Hello %s\n&quot;, name );              
</pre>

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